Introducing a novel pilot-scale vibrating reactor for fast pyrolysis of biomass

Typical fast pyrolysis reactors for bio-oil production such as fluidised-bed types apply high carrier gas flow and heat transfer medium. This inevitably requires high energy for heating and subsequent cooling of the carrier gas. Here, a novel vibrating reactor is proposed as an alternative reactor configuration for biomass pyrolysis. In this work, Leucaena leucocephala wood was pyrolysed using different parameters. It has been shown that the product distribution can be manipulated by controlling parameters related to the biomass and pyrolysis process, including pyrolysis temperature, reactor length/solid residence time, biomass feeding rate, biomass particle size, carrier gas flow rate and inlet gas pressure. Two fractions of bio-oils, the heavy and top-layer light bio-oils, were collected and analysed. The maximum bio-oil mass yield was 54 wt% comprising 36 wt% organics and 18 wt% reaction water. This mass yield was equivalent to 48% of the energy from biomass feedstock. In addition, the char mass yield of 23 wt% or 40% energy yield clearly indicated that the novel reactor is not only suitable for bio-oil production, but it is also appropriate for char production. Product analyses showed that the heavy bio-oil contained a high proportion of levoglucosan, which is regarded as a promising platform chemical for conversion to other high added-value chemicals. The light bio-oil contained high proportions of hydrocarbons including monocyclic aromatics such as BTX, alkanes, alkenes, cycloalkanes and cycloalkenes. The heavy bio-oil after water removal complied with most of the ASTM D7544-12 standard requirements. The char had an HHV of around 30 MJ/kg When combining the production of bio-oil and char, about 88% of the biomass energy was recovered in valuable products, and an indicative energy balance gave an energy output-to-input ratio of approximately 2.1, pointing to improved process economics for the novel vibrating reactor relative to the fluidised-bed alternative.